Solar energy systems comprise solar modules including solar cell arrays. In order to enhance efficiency of the energy conversion of solar modules, apparatuses for tracking the modules to the current position of the sun are known in the art. The tracker apparatuses are provided for optimizing the electrical output power of the solar modules by following the path of the sun crossing the sky or by employing calculation of ephemerides. Two-axes trackers allow for angular motion of the solar modules about the horizontal axis (“tilt”) and angular motion about the vertical axis (“rotation”).
Tracker apparatuses are necessary in concentrator photovoltaic (CPV) systems wherein they can guarantee that the solar radiation impinges (almost) vertically on the concentrator optics.
A typical tracker apparatus comprises a tracker table or frame on which the photovoltaic module is mounted, mechanical actuators (e.g., electrically driven motors) for adjusting the tracker table, and a (vertical) column or rod for holding the actuators and the tracker table. In particularly dangerous circumstances, e.g., heavy winds or gusts or a power breakdown of the electrical grid, the tracker table has to be moved into a “safety position,” i.e., basically horizontally, in order to prevent any damage done to the tracker table and the mounted photovoltaic module. In the art, central communication systems control the tracker apparatus to change the tracker table to a safety position by means of communication lines. Moreover, it is known to connect the actuators of the tracker apparatus directly to a control unit in order to enable the latter to directly cause the actuator to move the tracker table into the safety position. However, such conventional systems require expansive line routing and, in addition, may suffer from line breakage. If, for example, a communication line connection between a tracker control unit and the central communication system fails, the tracker table will not be brought into the safety position in case of danger or, as a means of precaution, will be operated to be in such a position in any case, i.e., usually without any actual risk of damage due to environmental effects, thereby reducing power production.
Thus, this disclosure addresses this underlying problem by providing a central safety system for the photovoltaic systems that reliably causes the tracker device to move into a safety position in case of danger without the need for a complex and expensive, as well as error-prone, line routing.